What licenses do I need to use Minecraft in class?

The children in my class would like a private lan server set up in school for MC. However I am a noob although I have played it via a vanilla server a while ago.

The school are willing to provide hardware and technical support but no financial for the immediate term until they are convinced it is worth while.

Do all versions of Minecraft require a paid for username in order to play?

Is it possible to setup a private offline LAN multiplayer server which the children can play while in school to build etc? If so, would we still require at least one username?

I don't mind paying once I have seen it in use but don't want to throw away money. The school are not forgiving.

Solution 1:

You can take a look at the demo version of Minecraft.

Yes, you will need one username for each player.

Also, take a look at MinecraftEdu

They offer Minecraft to schools for 50% off the retail price.

Solution 2:

Minecraft Demo can be used to host LAN, but it won't connect to a LAN server other than itself. So the only way to play Minecraft multiplayer without a paid account is to play the classic mode. It is, however, very old and only includes creative mode and limited maps.

For the actual up-to-date Minecraft, you need an account for each user. There seem to be ways to get accounts cheaper for schools, though.

Solution 3:

The current regular version of Minecraft intends to have one license/account per player, but no license is needed for the server.

Therefore, the only expense to make this happen, beyond server hardware, is Minecraft accounts for any player who does not already have one.